Clinical trials are used in the pharmaceutical industry to study human volunteers to answer specific health questions. Clinical trials are conducted in phases, with each phase having a different purpose. Phase I trials are used to test experimental drugs or treatments in a small group of people (20-80) to evaluate its safety, determine a safe dosage range, and identify side effects. Phase II trials are used to give the experimental drug or treatment to a larger group of people (100-300) to see if it is effective and to further evaluate its safety. Phase III trials are used to give the experimental drug or treatment to large groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the experimental drug or treatment to be used safely.
Clinical trials are conducted according to a specific protocol or study plan developed for each trial. The protocol is designed to increase the reliability of the study, as well as to safeguard the health of the participants and to answer specific research questions. The protocol typically describes what types of people may participate in the trial, the schedule of tests, procedures, medications, and dosages; and the length of the study. Participants following a protocol are typically seen regularly by the research staff to monitor their health and to determine the safety and effectiveness of their treatment.
During clinical trials, it is often difficult to know with certainty whether someone is taking a prescribed drug. Feces monitoring is done sometimes to make sure people are eating healthy. However, in most cases such feces monitoring does not provide conclusive proof that a particular drug has been ingested by the test subject. Adding a marker to the drug being tested has not been a viable option because of a concern for the safety of the test subject, as well as the potential interaction with the drug being tested and the effect on the clinical trial.
Markers are commonly used in the processed food industry to identify small quantities of returned food items that may or may not be in their original packaging, which may or may not be correctly identified by the person returning the item(s), or for any other of many reasons. Specific markers that can trace the identity of a food back to its original processing location are sometimes required by food manufacturers.
Markers in the food industry need to trace a wide range of processed foods, some of which cannot be readily adapted to having materials added to them. In some cases, sub-cellular markers may have to be used to provide identity. In others, cellular or multi-cellular materials may be used. Many spices and preservatives can be markers themselves, as well as in conjunction with morphological markers to provide additional specificity for product identifications. Sometimes a completed food item has components from several sources. Markers of different kinds are needed to identify the manufacturers of buns and meat patties that become part of a completed food product or system. The similarity of baked buns, for example, makes it critical for a supplier of buns to be able to identify their products from those of another supplier of buns used in the same restaurant or outlet. It is particularly critical when liability must be determined for foreign material reportedly found in a bun where two suppliers are used at the same location. In addition, the markers used in buns cannot confound those used in meats or condiments, and so forth.